In the laundry detergent field, numerous attempts have been made to formulate detergent compositions which provide the good cleaning performance expected of them and which also have good textile conditioning properties. Fabric conditioning agents found to provide antistatic and softening effects through the wash include quaternary ammonium compounds. Such compounds are preferably included in granular detergent compositions in a manner which minimizes their tendency to segregate out because of disparities in particle size. These quaternary ammonium compounds are preferably shielded in the wash water environment so that they are not inactivated by anionic surfactants commonly employed in laundering compositions. See U.S. Pat. Nos. 4,141,841, McDanald, issued Feb. 27, 1979, and 3,936,537, Baskerville, Jr. et al., issued Feb. 3, 1976.
Other antistatic/softening agents which also perform well in through-the-wash applications are imidazoline compounds of the formula: ##STR1## wherein R.sub.1 and R.sub.2 can independently be C.sub.12 to C.sub.20 hydrocarbyl groups. U.S. patent application Ser. No. 922,912, Baker et al., filed Oct. 24, 1986, discloses imidazoline compounds of a particle size between about 20 and about 200 microns which can be agglomerated, using any of a variety of binding agents known in the art, to form granular-sized (e.g., 1 millimeter) particles. Detergent compositions containing the agglomerates provide fabric care benefits as well as excellent cleaning performance.
U.S. patent application Ser. No. 102,183, Nesbitt et al., filed Sept. 29, 1987, describes an antistatic and softening particulate detergent additive comprised of the above imidazoline compound and nonaqueous agglomerating agent. Granular detergent compositions containing the additive are also described.
The above imidazoline compounds, unlike quaternary ammonium compounds, tend to hydrolyze during processing and storage. This hydrolysis opens the ringed imidazoline structure and forms the corresponding 1,3 dialkyl (or dialkenyl) amidodiethylenetriamine compound of the formula: ##STR2## wherein R.sub.1 and R.sub.2 are independently C.sub.12 to C.sub.20 hydrocarbyl groups (1,3 DDETA).
Mixtures of greater than about 75% by weight of the imidazoline compound, with the remainder 1,3 DDETA, are very effective softeners and static control agents when incorporated into granular detergents. Mixtures of between about 25% and about 75% by weight of the imidazoline compound with the remainder 1,3 DDETA, are much less effective fabric care agents.
Surprisingly, it has now been found that 1,3 DDETA alone, and mixtures of greater than about 75% by weight 1,3 DDETA, with the remainder the imidazoline compound, are again effective at softening fabrics and controlling static cling when incorporated into granular detergent or detergent additive compositions as particles. For mixtures containing less than 75% 1,3 DDETA (e.g., as low as 25% by weight) and other ingredients such as other fabric care actives or protective coating, the weight ratio of 1,3 DDETA to imidazoline compound should be at least about 3:1, preferably at least about 4:1, more preferably at least about 6:1, for best performance.
Detergent and additive compositions containing these particles also have good dryer compatibility, i.e., no dryer paint softening or lint screen blinding is observed. 1,3 DDETA also has a stability advantage over the imidazoline compound in that the former will not have its efficacy as softener and antistat reduced by hydrolysis.
It is an object of the present invention to provide a granular detergent or detergent additive composition incorporating discrete fabric care particles which are directly added to, and homogeneously admixed in, the composition.
It is also an object of the present invention to provide a granular detergent or detergent additive composition incorporating discrete fabric care particles which soften fabrics and reduce the tendency of fabrics washed in the composition to generate or retain static electricity when subjected to a subsequent machine drying process.
It is another object of the present invention to provide a granular detergent composition incorporating discrete fabric care particles which is capable of concurrently laundering, softening, and imparting antistat benefits to fabrics washed therewith and subsequently machine dried.